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09-01-2015, 03:33 AM   #16
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QuoteOriginally posted by Zygonyx Quote
The problem n1 is that two of them (btw, the latest) are not covering full 645 frame. And that is a first difference with Hasselblad. A strategic mistake imho.
do you know why the discontinued the D-FA645 25mm? Was it simply not good enough for full frame?

09-01-2015, 03:48 AM   #17
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I read the manufacturer of the glass was struck by insolvency.

Last edited by acoufap; 09-01-2015 at 03:56 AM.
09-01-2015, 04:55 AM   #18
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Exact, that's the official version at least, for front element(s).
And both 25mm versions are concerned.
09-01-2015, 05:30 AM   #19
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I was recently at a local photography store and have noticed they have more and more Pentax stuff. Not just that one drawer with lenses and three cameras, as it used to be. Now they have more stuff on display, and even a lot of spotting scopes and binoculars. And the Ricoh GR. I think two things are happening a) Ricoh is giving Pentax a little spending money for the marketing and b) Pentax 645Z made a big splash, so Pentax can build on this "renewed fame" (or is it infamy? )
Certainly looks like the 645D and Z are good products and are helping make the brand recognizable.

09-01-2015, 06:16 AM - 1 Like   #20
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You mean Pentax is no longer Doomed? How can this be? What will we do now? This is so disturbing!

Regards!
09-01-2015, 06:27 AM - 1 Like   #21
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why does one need/require a lens faster than f2.8 on medium format? The perceived depth of field your getting vs that of your 35mm would be similar to f1.4 already would it not? Or even thinner?

I shoot on my film 645 at f4 all the time because even at f2.8 your not getting the nose and the eyes in focus. I would prefer to stop down to f8, but I'm just not able to keep the shutter speed up high enough to prevent shake during golden hour.

thin DOF is overrated. :P
09-01-2015, 06:42 AM   #22
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Maybe, overrated but differenciating.
Be this btw sensor formats, bokeh and opticians
09-01-2015, 06:50 AM   #23
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QuoteOriginally posted by Zygonyx Quote
There are 16 645 format lenses in Pentax's current catalogue.
See here :
The PENTAX 645 lenses / PENTAX 645Z Special site | RICOH IMAGING
Problem n1 is that two of them (btw, the latest) are not covering full 645 frame. And that is a first difference with Hasselblad. A strategic mistake imho.
Problem n2 is that none of this lenses is faster than f/2.8 : hence no DOF advantage when compared (for the current 33x44mm sensor) to 35mm.
The biggest problem with the Pentax 645 lenses lineup is that most of the lenses date back to the '90s and their optical formula sometimes to the '80s. Only four of them are recent.

Hasselblad H lenses (by the way, three of them, the HCD lenses, are for cropped sensors too) and Phase One lenses are 21st century lenses.

And, among the 12 Hasselblad H and 19 Phase One lenses, only one is faster than f/2.8: the Hasselblad HC 100mm f/2.2. There is no disadvantage for Pentax there. More problematic is the absence of leaf shutter lenses in the Pentax 645 lineup.

09-01-2015, 06:53 AM   #24
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QuoteQuote:
The Pentax feels like a partner. Its working with you, not for you or against you. It feels like its trying to help you create the best possible images.
I think this conlusion could be applied to all Pentax bodies, not just the 645Z. Or, at least, this is exactly why I've always prefered Pentax cameras over other brands.
09-01-2015, 06:54 AM   #25
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QuoteOriginally posted by gazonk Quote
do you know why the discontinued the D-FA645 25mm? Was it simply not good enough for full frame?
QuoteOriginally posted by acoufap Quote
I read the manufacturer of the glass was struck by insolvency.
Pentax D-FA645 25mm f/4 was very expensive to manufacture, in particular the precise centring of the various element was very complicated. Hence the DA645 version, easier to produce (centring is less an issue with a reduced image circle), and the D-FA645 version being limited to Japan where there are still a lot of Pentax 645 from the film era.

More recently one of the elements became impossible to procure, hence the discontinuing of both versions.

---------- Post added 09-01-2015 at 04:05 PM ----------

QuoteOriginally posted by Wired Quote
why does one need/require a lens faster than f2.8 on medium format? The perceived depth of field your getting vs that of your 35mm would be similar to f1.4 already would it not? Or even thinner?

I shoot on my film 645 at f4 all the time because even at f2.8 your not getting the nose and the eyes in focus. I would prefer to stop down to f8, but I'm just not able to keep the shutter speed up high enough to prevent shake during golden hour.

thin DOF is overrated. :P
In terms of perceived depth of field, f/2.8 on a digital Pentax 645 camera (33x44mm sensor) is equivalent to f/2.2 on a 24x36 camera and f/2.8 on a film 645 camera (41.5x56mm) is equivalent to f/1.7 on a 24x36 camera.

But I agree with you: the main advantage of medium format is the progressiveness in the net --> blurred transitions and the "legibility" of the blurred zones at medium apertures such as f/4 or f/5.6.
09-01-2015, 07:26 AM   #26
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QuoteOriginally posted by Mistral75 Quote
Pentax D-FA645 25mm f/4 was very expensive to manufacture, in particular the precise centring of the various element was very complicated. Hence the DA645 version, easier to produce (centring is less an issue with a reduced image circle), and the D-FA645 version being limited to Japan where there are still a lot of Pentax 645 from the film era.

More recently one of the elements became impossible to procure, hence the discontinuing of both versions.

---------- Post added 09-01-2015 at 04:05 PM ----------




But I agree with you: the main advantage of medium format is the progressiveness in the net --> blurred transitions and the "legibility" of the blurred zones at medium apertures such as f/4 or f/5.6.
thats what I always assumed was the big thing with MF. things just look softer and more dynamic at the same time.


At the end of the day it depends on what your shooting. A photographer in a studio or landscape environment will rarely need wide open apertures. When I'm in studio I'm usually between f8-f11.
09-01-2015, 07:51 AM   #27
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QuoteOriginally posted by Tom S. Quote
Agreed! I always suspect reviews in which a company gives the reviewer the product.
I used to think that too... until I actually started getting asked to do reviews. The problem being this - it takes time to give the eq a thorough test, to learn to use the eq, it takes time and thought to write a sensible review, and it takes time to upload it onto websites. These companies benefit from reviews, heck they may even quote them on their literature or website and use any shots you do with it. Yet these same companies quite happily make profit from us by selling us equipment at expensive prices. So I just don't see why this shouldn't be a two way street, and if they expect us to help them out to make them their profit, they can give me something in return!

But I think this is where the trickiness starts, because when you're given something sure it's a natural impulse to be grateful and in return give an overly good review. I think the really excellent reviewer has to remain objective and not let anything influence their review, and be open about being compensated for their time in their review. Beyond that, the review has to speak for itself. People soon twig if it's a paper thin 'just read the mfr specs and rewrote the blurb' "review" (many are, especially online) or a decent review from someone who takes some time to properly learn, use, evaluate and compare the product, giving it some good field use. I have several things currently in this category, all of which I'm currently evaluating. And I've turned away every company that's asked me to review without any compensation, I simply value my time too much and whilst I love companies that make this stuff, I have no illusion about them being anything other than profit-making enterprises at consumer expense.
09-01-2015, 08:02 AM   #28
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QuoteOriginally posted by Nass Quote
I used to think that too... until I actually started getting asked to do reviews. The problem being this - it takes time to give the eq a thorough test, to learn to use the eq, it takes time and thought to write a sensible review, and it takes time to upload it onto websites. These companies benefit from reviews, heck they may even quote them on their literature or website and use any shots you do with it. Yet these same companies quite happily make profit from us by selling us equipment at expensive prices. So I just don't see why this shouldn't be a two way street, and if they expect us to help them out to make them their profit, they can give me something in return!

But I think this is where the trickiness starts, because when you're given something sure it's a natural impulse to be grateful and in return give an overly good review. I think the really excellent reviewer has to remain objective and not let anything influence their review, and be open about being compensated for their time in their review. Beyond that, the review has to speak for itself. People soon twig if it's a paper thin 'just read the mfr specs and rewrote the blurb' "review" (many are, especially online) or a decent review from someone who takes some time to properly learn, use, evaluate and compare the product, giving it some good field use. I have several things currently in this category, all of which I'm currently evaluating. And I've turned away every company that's asked me to review without any compensation, I simply value my time too much and whilst I love companies that make this stuff, I have no illusion about them being anything other than profit-making enterprises at consumer expense.
this is why I love the TCStv reviews, they are the most objective reviews i've watched or read online
09-01-2015, 08:17 AM - 2 Likes   #29
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QuoteOriginally posted by Wired Quote
why does one need/require a lens faster than f2.8 on medium format?
Pentax needs to make a 645 lens with f1.8 aperture. Just to shut up all the "omg more bokeh" people. It doesn't even have to be good, just expensive with a lot of aperture blades.
09-01-2015, 08:33 AM   #30
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QuoteOriginally posted by Wired Quote
why does one need/require a lens faster than f2.8 on medium format?
Do you have a 55/2.8 for your FF camera? Would you consider that a fast, middle or slow lens on a FF camera?

The 645D/Z has a 55mm sold as its normal lens. IMHO, its not much of a medium format coming from shooting ~100mm as a normal lens on a medium format camera. Until the sensor gets larger on MFD do we draw the comparisons of DOF with max aperture to legacy medium format cameras. The jump from FF to 645D/Z is less than the jump from APS-C to FF in terms difference in sensor sizes. So I say, yes, f2.8 is pretty much just as "slow" or "fast" on a 645D/Z as a FF camera.

When other manufactures start entering the MFD arena, I suspect we will see far more capable sports action from these MFD cameras as well as faster glass.
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